Illumination control for imaging systems with multiple image sensors

ABSTRACT

Embodiments of the disclosure relate generally to illumination synchronization in a multi-imager environment. Embodiments include systems, methods, computer program products, and apparatuses configured for operating a near-field illumination source associated with a near-field image sensor, based on a first illumination pulse train. An exposure period of a far-field image sensor is determined and one or more characteristics of the first illumination pulse train are modified to accommodate the exposure period of the far-field image sensor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/157,979, titled “ILLUMINATION CONTROL FOR IMAGING SYSTEMS WITHMULTIPLE IMAGE SENSORS,” filed Jan. 25, 2021, the contents of which areincorporated herein by reference in their entirety.

TECHNOLOGICAL FIELD

Embodiments of the present disclosure generally relates to an imagingsystem with multiple image sensors, and more particularly toillumination control for image sensors of the imaging system.

BACKGROUND

Imaging devices and systems have found application in areas that aremore sophisticated and advanced than mere photography. There has been aconstant demand for improvement in the imaging capabilities of thesedevices and systems to fit support the new capabilities. With currentlyavailable imaging systems, factors such as miniaturized form factor haveled to increase in interference between components of the imagingsystems. In such systems, it remains a challenge to operate thecomponents in a synchronized manner so as to prevent any adverse effecton each other's capabilities.

SUMMARY

In general, embodiments of the present disclosure provided herein areconfigured for illumination control and synchronization in amulti-imager environment. Other implementations for one or more of thealternative illuminator assemblies and/or alternative illuminationimaging systems and apparatuses will be, or will become, apparent to onewith skill in the art upon examination of the following figures anddetailed description. It is intended that all such additionalimplementations be included within this description, be within the scopeof the disclosure, and be protected by the following claims.

In accordance with some example embodiments, provided herein is animaging system. In an example embodiment, the imaging system comprises afirst illumination source associated with a first image sensor, thefirst illumination source being configured to operate based on a firstillumination pulse train. The imaging system also comprises a secondimage sensor, and a controller communicatively coupled to each of thefirst illumination source, the first image sensor and the second imagesensor. In some example embodiments, the controller is configured todetermine a first exposure period of the second image sensor and modifyone or more characteristics of the first illumination pulse train toaccommodate the first exposure period of the second image sensor.

Additionally or alternatively, in some embodiments of the imagingsystem, to modify the one or more characteristics of the firstillumination pulse train, the controller is further configured to insertat least one additional illumination pulse in the first illuminationpulse train such that one of a start time period or an end time periodof an illumination period of the at least one additional illuminationpulse is aligned with a respective one of a start time period or an endtime period of the first exposure period of the second image sensor.

Additionally or alternatively, in some embodiments of the imagingsystem, to modify the one or more characteristics of the firstillumination pulse train, the controller is further configured to insertat least one additional illumination pulse in the first illuminationpulse train such that illumination of the first image sensorcorresponding to the at least one additional illumination pulsetemporally overlaps an autofocus period of the second image sensor.

Additionally or alternatively, in some embodiments of the imagingsystem, to modify the one or more characteristics of the firstillumination pulse train, the controller is further configured toincrease a timing delay between a pair of temporally subsequentillumination pulses of the first illumination pulse train such that oneof a start time period or an end time period of the first exposureperiod is aligned with a respective one of a start time period or an endtime period of the increased timing delay.

Additionally or alternatively, in some embodiments of the imagingsystem, the first image sensor is exposed during at least a secondexposure period. In some example embodiments, the exposure of the firstimage sensor during the second exposure period begins simultaneouslywith a start time period of a first illumination pulse of the firstillumination pulse train, and an end time period of the second exposureperiod extends beyond an end time period of the first illumination pulseof the first illumination pulse train.

Additionally or alternatively, in some embodiments of the imagingsystem, the controller is further configured to obtain an image framecaptured by exposure of the second image sensor during the firstexposure period. In some example embodiments, the controller is furtherconfigured to determine a brightness of the image frame and activate asecond illumination source associated with the second image sensor,based on the determined brightness of the image frame, wherein thesecond illumination source is configured to operate based on a secondillumination pulse train.

Additionally or alternatively, in some embodiments of the imagingsystem, exposure of the first image sensor begins simultaneously withactivation of the first illumination source.

Additionally or alternatively, in some embodiments of the imagingsystem, the second image sensor remains deactivated during a firstillumination period of a first illumination pulse of the firstillumination pulse train. Additionally or alternatively, in someembodiments, the second image sensor is exposed during a part of asecond illumination period of a second illumination pulse of the firstillumination pulse train.

In some example embodiments, an imaging method is provided. The methodmay be implemented using any one of a myriad of implementations, such asvia hardware, software, and/or firmware of a multi-sensor imaging engineand/or multi-sensor imaging apparatus as described herein. In someexample implementations of the method, the example method includesoperating a first illumination source associated with a first imagesensor, based on a first illumination pulse train. The example methodfurther includes determining a first exposure period of a second imagesensor and modifying one or more characteristics of the firstillumination pulse train to accommodate the first exposure period of thesecond image sensor.

Additionally or alternatively, in some embodiments of the method,modifying the one or more characteristics of the first illuminationpulse train comprises inserting at least one additional illuminationpulse in the first illumination pulse train such that one of a starttime period or an end time period of an illumination period of the atleast one additional illumination pulse is aligned with a respective oneof a start time period or an end time period of the first exposureperiod of the second image sensor.

Additionally or alternatively, in some embodiments of the method,modifying the one or more characteristics of the first illuminationpulse train comprises inserting at least one additional illuminationpulse in the first illumination pulse train such that illumination ofthe first image sensor corresponding to the at least one additionalillumination pulse temporally overlaps an autofocus period of the secondimage sensor.

Additionally or alternatively, in some embodiments of the method,modifying the one or more characteristics of the first illuminationpulse train comprises increase a timing delay between a pair oftemporally subsequent illumination pulses of the first illuminationpulse train such that one of a start time period or an end time periodof the first exposure period is aligned with a respective one of a starttime period or an end time period of the increased timing delay.

Additionally or alternatively, in some embodiments of the method, themethod further comprises causing exposure of the first image sensorduring at least a second exposure period. In some example embodiments,the exposure of the first image sensor during the second exposure periodbegins simultaneously with a start time period of a first illuminationpulse of the first illumination pulse train. In some exampleembodiments, an end time period of the second exposure period extendsbeyond an end time period of the first illumination pulse of the firstillumination pulse train.

Additionally or alternatively, in some embodiments of the method, themethod further comprises obtaining an image frame captured by exposureof the second image sensor during the first exposure period. The examplemethod further includes determining a brightness of the image frame andactivating a second illumination source associated with the second imagesensor, based on the determined brightness of the image frame, thesecond illumination source being configured to operate based on a secondillumination pulse train.

In some example embodiments, an apparatus is provided. In an exampleembodiment, the apparatus comprises a memory configured to storeexecutable instructions and one or more processors. In some exampleembodiments, the one or more processors are configured to execute theexecutable instructions to control operation of a first illuminationsource associated with a first image sensor, based on a firstillumination pulse train. In some example embodiments, the one or moreprocessors are further configured to determine a first exposure periodof a second image sensor and modify one or more characteristics of thefirst illumination pulse train to accommodate the first exposure periodof the second image sensor.

Additionally or alternatively, in some embodiments of the apparatus, tomodify the one or more characteristics of the first illumination pulsetrain, the one or more processors are further configured to insert atleast one additional illumination pulse in the first illumination pulsetrain such that one of a start time period or an end time period of anillumination period of the at least one additional illumination pulse isaligned with a respective one of a start time period or an end timeperiod of the first exposure period of the second image sensor.

Additionally or alternatively, in some embodiments of the apparatus, tomodify the one or more characteristics of the first illumination pulsetrain, the one or more processors are further configured to insert atleast one additional illumination pulse in the first illumination pulsetrain such that illumination of the first image sensor corresponding tothe at least one additional illumination pulse temporally overlaps anautofocus period of the second image sensor.

Additionally or alternatively, in some embodiments of the apparatus, tomodify the one or more characteristics of the first illumination pulsetrain, the one or more processors are further configured to increase atiming delay between a pair of temporally subsequent illumination pulsesof the first illumination pulse train such that one of a start timeperiod or an end time period of the first exposure period is alignedwith a respective one of a start time period or an end time period ofthe increased timing delay.

Additionally or alternatively, in some embodiments of the apparatus, theone or more processors are further configured to obtain an image framecaptured by exposure of the second image sensor during the firstexposure period. In some example embodiments of the apparatus, the oneor more processors are further configured to determine a brightness ofthe image frame and activate a second illumination source associatedwith the second image sensor, based on the determined brightness of theimage frame, wherein the second illumination source is configured tooperate based on a second illumination pulse train.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described the embodiments of the disclosure in generalterms, reference now will be made to the accompanying drawings, whichare not necessarily drawn to scale, and wherein:

FIG. 1A illustrates a block diagram of an example multi-sensor imagingsystem, in accordance with an example embodiment of the presentdisclosure;

FIG. 1B illustrates a block diagram of an example multi-sensor imagingengine, in accordance with an example embodiment of the presentdisclosure;

FIG. 2 illustrates a block diagram of an example multi-sensor imagingapparatus, in accordance with an example embodiment of the presentdisclosure;

FIG. 3 illustrates a visualization of field of views associated with anexample multi-sensor imaging apparatus, in accordance with an exampleembodiment of the present disclosure;

FIG. 4 illustrates a visualization of a first illumination produced byan example multi-sensor imaging system, in accordance with an exampleembodiment of the present disclosure;

FIG. 5 illustrates a visualization of a second illumination produced byan example multi-sensor imaging system, in accordance with an exampleembodiment of the present disclosure;

FIG. 6 illustrates a timing diagram associated with operationalfunctionality of an example multi-sensor imaging system, in accordancewith an example embodiment of the present disclosure;

FIG. 7 illustrates a flowchart depicting example operations of a processfor illumination control in a multi-imager environment, in accordancewith an example embodiment of the present disclosure;

FIG. 8 illustrates a flowchart depicting example operations of a processfor modifying one or more characteristics of a first illumination pulsetrain to accommodate a first exposure period of a second image sensor ofan example multi-sensor imaging system, in accordance with an exampleembodiment of the present disclosure;

FIG. 9 illustrates a flowchart depicting example operations of anotherprocess for modifying one or more characteristics of a firstillumination pulse train to accommodate a first exposure period of asecond image sensor of an example multi-sensor imaging system, inaccordance with an example embodiment of the present disclosure;

FIG. 10 illustrates a flowchart depicting example operations of anotherprocess for modifying one or more characteristics of a firstillumination pulse train to accommodate a first exposure period of asecond image sensor of an example multi-sensor imaging system, inaccordance with an example embodiment of the present disclosure;

FIG. 11 illustrates a timing diagram associated with operationalfunctionality of an example multi-sensor imaging system for flickerreduction, in accordance with an example embodiment of the presentdisclosure;

FIGS. 12A, 12B, and 12C illustrate an example workflow of a symboldecoding process, in accordance with an example embodiment of thepresent disclosure;

FIG. 13 illustrates an example workflow of a flicker reduction process,in accordance with an example embodiment of the present disclosure; and

FIG. 14 illustrates an example workflow of a flicker reduction processfor extended far field exposures of an imaging apparatus in accordancewith an example embodiment of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure now will be described more fullyhereinafter with reference to the accompanying drawings, in which some,but not all, embodiments of the disclosure are shown. Indeed,embodiments of the disclosure may be embodied in many different formsand should not be construed as limited to the embodiments set forthherein, rather, these embodiments are provided so that this disclosurewill satisfy applicable legal requirements. Like numbers refer to likeelements throughout.

Imaging apparatuses, such as indicia readers, are used in a variety ofscenarios, each requiring a specific set of imaging requirements to bemet so that an operation associated with the indicia reader such assymbol decoding may be successively carried out. Additionally, certainsafety requirements, for example pertaining to the operator of theindicia reader, have to be satisfied to ensure compliance with statutoryrules. Indicia readers usually require a symbol affixed on a surface tobe scanned from a close range to successfully decode them. However, insome environments such as warehouses, it is not possible to scan andsuccessively decode symbols affixed on parcels and consignments byreaching out to each consignment from a close range. As such, anextended range indicia reader is provided which does not require anoperator to individually reach out to each consignment from a closerange. Such an extended range indicia reader is able to scan multiplesymbols from a single operator position owing to the far field scanningcapability of the extended range reader. Such indicia readers includemultiple image sensors and associated optics to provide thesecapabilities.

The illumination requirements of the sensors may vary greatly. Forexample, while one or more image sensors of the indicia reader mayrequire illumination even during data read-out, other sensors may not.As such, keeping the light source of one image sensor activated for alonger period may result in interference with the exposure period ofanother sensor for which illumination is not desired. Such interferencemay result in images that are flawed in terms of one or more imagingcharacteristics, thereby negatively impacting the resultant imageprocessing task. The problem is especially prevalent in miniaturizedimaging devices in which the sensors, illumination sources, and otheroptics and components are placed closely. Further, in the context ofmulti-imager environments (e.g., including multiple imagers and/ormultiple light sources), naïve implementations for capturing images,such as by alternating between imagers and/or light sources, exacerbateflickering effects, and therefore exacerbate the negative effectsassociated therewith.

Often in scenarios where the image sensors are of different types, it isdifficult to synchronize the illuminations of the sensors for successfuloperation. For example, when the indicia reader includes a rollingshutter sensor for imaging in the far field and a global shutter sensorfor imaging in the near field, it becomes difficult to ensure optimumillumination conditions for the global shutter sensor due to extendedillumination time of the rolling shutter during data readout. Thisresults in producing undesired effects such as snappiness in the imagecaptured by the global shutter sensor. Further, the extendedillumination time may also result in heat generation that impacts theheat management system in the barcode scanner. Furthermore, in outdoorenvironments illumination may not always be required for far fieldimaging due to sufficient ambient light being available. As such, theaimer of the imaging system may not be distinguishable from thebackground, thereby requiring quick focus to adjust the focus positionof the image sensor.

Additionally, controlling the illumination of such apparatuses is usefulfor providing a visual appearance that is preferable to operators. Forexample, if an illumination pulse is within a certain frequency range(e.g., below a certain threshold frequency), the operator couldexperience headaches and/or seizures from viewing exposure to theillumination. In multi-imager contexts having a plurality ofillumination sources, each illumination source should be configuredaccordingly to prevent such negative health effects and undesired visualappearance. Regardless, if illumination sources are cycled throughand/or otherwise often switched between, the operator may experience a“flickering” effect that may be undesirable or harmful as well.

Some embodiments described herein relate to a dual illuminationframework for multi-sensor imaging systems that include multipleillumination sources and multiple image sensors. Some embodimentsdescribed herein utilize a first illumination source and a first imagesensor for capturing image(s) during one or more illumination pulses ofan illumination pulse train associated with the first illuminationsource. Embodiments further capture images utilizing a second imagesensor, where the exposure period of the second image sensor isconsidered to modify the first illumination pulse train such that theillumination of the first illumination source does not introduce anyundesired effect in the image captured by the second image sensor.Further, the illumination of the second image sensor is timed in amanner that does not affect the image captured by the first imagesensor.

In some embodiments, one or more events may be triggered indicatingcircumstances where activation of a second illumination source isrequired. In this regard, the second illumination source may produce asecond illumination for illuminating a second field of view associatedwith the second image sensor. In one such example context, theactivation of the second illumination source is triggered afterdetermining that an object is not detectable within the captured imagesin a first field of view using the first illumination source and/or inthe second field of view using ambient light illumination, and thus islikely at a further distance from the imaging apparatus. The activationof the second illumination source may be triggered in response todetecting one or more events and/or circumstances, for example inresponse to processing one or more previously captured images todetermine a threshold number of images have been captured, and that noobject is detectable within the captured images in very low lightingconditions (e.g., below a certain white value threshold).

In such circumstances, the change to another illumination source enablesthe second image sensor to be triggered during the illumination pulsesof the newly activated second illumination source to improve theeffective reading range of the apparatus. In embodiments having morethan two illumination sources, the same considerations may continue forcycling through more than two illumination sources, for examplenarrowing the field of view illuminated by each illumination source andextending the effective range with each cycle. Alternatively, one ormore illumination sources may be skipped, for example where the cycleimmediately proceeds from a broadest illumination source to a narrowestillumination source without utilizing one or more intermediateillumination source(s).

Such embodiments provide effective synchronization of the illuminationsources with flicker reduction and/or flicker elimination while enablingeffective and efficient capturing of images for processing. Theoperation of such embodiments captures images in a manner likely toresult in successfully completing an image processing task, such asindicia or symbol scanning, while increasing the likelihood an image iscaptured within a desired operational time frame that includes datasufficient for successful processing. By way of implementation ofvarious example embodiments described herein, an operational efficiencyof the imaging apparatus is maintained or improved while addressing thechallenges arising out of usage of multiple sensors and illuminationsources.

In some embodiments, some of the operations above may be modified orfurther amplified. Furthermore, in some embodiments, additional optionaloperations may be included. Modifications, amplifications, or additionsto the operations above may be performed in any order and in anycombination.

Many modifications and other embodiments of the disclosure set forthherein will come to mind to one skilled in the art to which thisdisclosure pertains having the benefit of the teachings presented in theforegoing description and the associated drawings. Therefore, it is tobe understood that the embodiments are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Moreover, although the foregoing descriptions and the associateddrawings describe example embodiments in the context of certain examplecombinations of elements and/or functions, it should be appreciated thatdifferent combinations of elements and/or functions may be provided byalternative embodiments without departing from the scope of the appendedclaims. In this regard, for example, different combinations of elementsand/or functions than those explicitly described above are alsocontemplated as may be set forth in some of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

Definitions

The term “illumination” refers to one or more light rays produced by anillumination source within a defined field of view. In at least oneexample context, the illumination includes one or more illuminationpulses produced by a corresponding illumination source. In someembodiments, an illumination is produced based on a “defined pulsefrequency,” which refers to a rate at which illumination pulses areproduced by an illumination source. Additionally or alternatively, insome embodiments, an illumination is produced based on a “defined pulsephase,” which refers to a period of activation for which an illuminationsource is producing a corresponding illumination.

Thus, multiple illumination pulses with a defined pulse frequencytogether may constitute an “illumination pulse train”. Each illuminationpulse may extend in time domain for a duration referred to as“illumination period”. Thus, the illumination period may refer to thetime duration for which an amplitude of the illumination pulse remainsnon-zero. That is, illumination period of an illumination pulse refersto the period for which the illumination source remains activatedcorresponding to the illumination pulse.

In at least one example context, an illumination pulse is associatedwith an “illumination pulse start time,” which refers to electronicallymanaged data representing a time at which a corresponding illuminationsource will begin producing the illumination pulse. Additionally oralternatively, in at least one such context, an illumination pulse isassociated with an “illumination pulse end time,” which refers toelectronically managed data representing a time at which a correspondingillumination source will cease producing the illumination pulse.

The term “start time period of an illumination period” refers to a timeperiod of a threshold duration starting from an illumination pulse starttime, where the threshold duration may have a configurable value. In atleast one example context, the threshold duration may be zero and assuch, the term start time period of an illumination period and theillumination pulse start time may refer to the same instance in time.Each illumination pulse may have an individual start time period.

The term “end time period of an illumination period” refers to a timeperiod of a threshold duration ending at an illumination pulse end time,where the threshold duration may have a configurable value. In at leastone example context, the threshold duration may be zero and as such, theterm end time period of an illumination period and the illuminationpulse end time may refer to the same instance in time. Each illuminationpulse may have an individual end time period.

The term “illumination source” (also referred to as “illuminator source”or “illuminator”) refers to one or more light generating hardware,devices, and/or components configured to produce an illumination withina desired field of view. Non-limiting examples of an illumination sourceincludes one or more light emitting diode(s) (LEDs), laser(s), and/orthe like.

The term “near-field illumination source” refers to an illuminationsource configured to produce an illumination for illuminating anear-field of view associated with a near-field image sensor. In atleast one example context, the near-field illumination source isconfigured to produce an illumination in a wider field of view ascompared to that of a far-field illumination source.

The term “far-field illumination source” refers to an illuminationsource configured to produce an illumination for illuminating afar-field of view associated with a far-field imager. In at least oneexample context, the far-field illumination source is configured toproduce an illumination in a narrower field of view as compared to thatof a near-field illumination source.

The term “near-field illumination” refers to a particular illuminationproduced by a near-field illumination source. In some embodiments, thenear-field illumination is associated with illumination of a near fieldof view captured by a near-field image sensor. The term “near-fieldillumination pulse” refers to an illumination pulse of a near-fieldillumination associated with a near-field sensor.

The term “far-field illumination” refers to a particular illuminationproduced by a far-field illumination source. In some embodiments, thefar-field illumination is associated with illumination of a far field ofview captured by a far-field image sensor. The term “far-fieldillumination pulse” refers to an illumination pulse of a far-fieldillumination.

The term “imager” refers to one or more components configured forcapturing an image representing a particular field of view. In at leastone example context, an imager includes at least one optical component(e.g., lens(es) and/or associated housing(s)) defining a particularfield of view. Additionally or alternatively, in at least one examplecontext, an imager includes an image sensor configured to output animage based on light that engages with the image sensor, such as via theoptical components.

The term “image sensor” refers to one or more components configured togenerate an image represented by a data object based on light incidenton the image sensor. In some such example contexts, an image sensorconverts light waves that interact with the image sensor into signalsrepresenting an image output by the sensor.

The term “near-field image sensor” refers to an image sensor configuredfor capturing an image of a near field of view. In at least one context,the near-field image sensor comprises at least one near-field opticalcomponent(s) defining the near field of view, and an electronic sensor.In at least one example context, the near-field image sensor may includea global shutter. In some example contexts, the near-field image sensormay include a rolling shutter. The term “near-field image” refers toelectronic data generated by the near-field image sensor that embodies acaptured representation of the near field of view.

The term “far-field image sensor” refers to an image sensor configuredfor capturing an image of a far-field of view. In at least one context,the far-field image sensor comprises at least one far-field opticalcomponent(s) defining the far field of view, and an electronic sensor.In at least one example context, the far-field image sensor may includea rolling shutter. In some example contexts, the far-field image sensormay include a global shutter. The term “far-field image” refers toelectronic data generated by the far-field image sensor that embodies acaptured representation of the far field of view.

The term “exposure period” refers to electronic data representing alength of time that an image sensor is configured for exposure tooncoming light. In at least one example embodiment, an image sensor ofan imager is configured to utilize a variable exposure time that may beset to a particular exposure time value.

The term “start time period of an exposure period” refers to a timeperiod of a threshold duration starting from a start of the exposureperiod. The threshold duration may have a configurable value. In oneexample, the threshold duration may be zero and as such, the term starttime period of an exposure period and the start of the exposure periodmay refer to the same instance in time.

The term “end time period of an exposure period” refers to a time periodof a threshold duration ending at an end of the exposure period wherethe threshold duration may have a configurable value. In one example,the threshold duration may be zero and as such, the term end time periodof an exposure period and the end of the exposure period may refer tothe same instance in time.

FIG. 1A illustrates a block diagram of an example multi-sensor imagingsystem 10 (hereinafter, also referred to as imaging system 10), inaccordance with an example embodiment of the present disclosure. Themulti-sensor imaging system 10 includes an imaging engine 100communicatively coupled with a controller 20, a communication interface40, an activation component 60, and one or more peripheral components80. In some example embodiments, the imaging system 10 may include feweror more components than shown in FIG. 1A. The imaging system 10 isconfigured for capturing one or more images of a target in one or morefields of views using one or more illumination sources. The imagingsystem 10 processes the one or more images to execute one or more imageprocessing tasks such as indicia reading. Accordingly, in some exampleembodiments of the disclosure, the imaging system 10 may be embodied inpart or full as an indicia or symbol reader or a handheld device capableof reading indicia and similar symbols. One example embodiment of theimaging system 10 is illustrated in FIG. 2 , details of which will bedescribed in the subsequent portions of the disclosure.

Controller 20 may be configured to carry out one or more controloperations associated with the imaging system 10. For example,controller 20 may control the imaging engine 100 to cause image captureof a target in a field of view of the imaging engine 100. Additionally,the controller 20 may process the captured images to carry out one ormore image processing tasks. The controller 20 may be embodied as acentral processing unit (CPU) comprising one or more processors and amemory. In some example embodiments, the controller 20 may be realizedusing one or more microcontroller units (MCU), as one or more of varioushardware processing means such as a coprocessor, a microprocessor, adigital signal processor (DSP), a processing element with or without anaccompanying DSP, or various other processing circuitry includingintegrated circuits such as, for example, an ASIC (application specificintegrated circuit), an FPGA (field programmable gate array), a hardwareaccelerator, a special-purpose computer chip, or the like. In someembodiments, the processor of the controller 20 may include one or moreprocessing cores configured to operate independently. A multi-coreprocessor may enable multiprocessing within a single physical package.Additionally, or alternatively, the processor may include one or moreprocessors configured in tandem via the bus to enable independentexecution of instructions, pipelining and/or multithreading.

The memory may be non-transitory and may include, for example, one ormore volatile and/or non-volatile memories. For example, the memory maybe an electronic storage device (for example, a computer readablestorage medium) comprising gates configured to store data (for example,bits) that may be retrievable by a machine (for example, a computingdevice like the processor). The memory may be configured to storeinformation, data, content, applications, instructions, or the like, forenabling the apparatus to carry out various functions in accordance withan example embodiment of the present invention. For example, the memorycould be configured to buffer data for processing by the processor.Additionally, or alternatively, the memory could be configured to storeinstructions for execution by the processor.

The processor (and/or co-processors or any other processing circuitryassisting or otherwise associated with the processor) may be incommunication with the memory via a bus for passing information amongcomponents of the imaging system 10. The processor may be configured toexecute instructions stored in the memory or otherwise accessible to theprocessor. Additionally, or alternatively, the processor may beconfigured to execute hard coded functionality. As such, whetherconfigured by hardware or software methods, or by a combination thereof,the processor may represent an entity (for example, physically embodiedin circuitry) capable of performing operations according to anembodiment of the present invention while configured accordingly. Thus,for example, when the processor is embodied as an ASIC, FPGA or thelike, the processor may be specifically configured hardware forconducting the operations described herein. Alternatively, as anotherexample, when the processor is embodied as an executor of softwareinstructions, the instructions may specifically configure the processorto perform the algorithms and/or operations described herein when theinstructions are executed. The processor may include, among otherthings, a clock, an arithmetic logic unit (ALU) and logic gatesconfigured to support operation of the controller 20.

The communication interface 40 may comprise input interface and outputinterface for supporting communications to and from the imaging system10. The communication interface 40 may be any means such as a device orcircuitry embodied in either hardware or a combination of hardware andsoftware that is configured to receive and/or transmit data to/from acommunications device in communication with the imaging system 10. Inthis regard, the communication interface 40 may include, for example, anantenna (or multiple antennae) and supporting hardware and/or softwarefor enabling communications with a wireless communication network.Additionally or alternatively, the communication interface 40 mayinclude the circuitry for interacting with the antenna(s) to causetransmission of signals via the antenna(s) or to handle receipt ofsignals received via the antenna(s). In some environments, thecommunication interface 40 may alternatively or additionally supportwired communication. As such, for example, the communication interface40 may include a communication modem and/or other hardware and/orsoftware for supporting communication via cable, digital subscriber line(DSL), universal serial bus (USB) or other mechanisms.

The activation component 60 may include hardware, software, firmware,and/or a combination thereof, configured to indicate initiation (and/ortermination) of desired functionality by the user. For example, theactivation component 60 may transmit an activation signal to cause thecontroller 20 to begin operation of the imaging engine 100, for exampleto begin illumination by one or more illumination sources, and/orcapture by image sensors, one or more images. Additionally oralternatively, the activation component 60 may transmit a deactivationsignal to the controller 20 to terminate the correspondingfunctionality, for example to cease scanning via the image sensor(s). Insome embodiments, the activation component 60 is embodied by one or morebuttons, triggers, and/or other physical components provided in or onthe body of a chassis. For example, in at least one example context, theactivation component 60 is embodied by one or more “trigger” componentsthat, when engaged by an operator (e.g., when an operator squeezes thetrigger), transmits a signal to the controller 20 to initiatecorresponding functionality. In some such embodiments, the activationcomponent may transmit a deactivation signal to the controller 20 tocease such functionality when the component is disengaged by theoperator (e.g., when the operator releases the trigger). Alternativelyor additionally, in at least some embodiments, the activation component60 is embodied without any components for direct engagement by anoperator. For example, when the imaging system 10 is embodied as animaging apparatus, the activation component 60 may be embodied byhardware and/or software, or a combination thereof, for detecting theimaging apparatus has been raised and/or positioned to a predefined“scanning” position, and/or lowered from that position to triggerdeactivation. Alternatively or additionally, the activation component 60may be embodied as a user interface element of the imaging system 10. Insuch embodiments, the activation component 60 embodied as a userinterface element may be configured to receive an input from the user ona user interface and in turn transmit a corresponding command to thecontroller 20.

The one or more peripheral components 80 include other structural andfunctional elements of the imaging system 10 such as for example adisplay device, a user interface, a housing, a chassis, power source andthe like. One or more of the peripheral components 80 may be controlledby the controller and may operate as per instructions or controlprovided by the controller 20.

FIG. 1B illustrates an example multi-sensor imaging engine (hereinafter,also referred to as “imaging engine”) in accordance with an exampleembodiment of the present disclosure. Specifically, as illustrated, theexample multi-sensor imaging engine is embodied by a multi-sensorimaging engine 100. The multi-sensor imaging engine 100 includes aplurality of image sensors, specifically a near-field image sensor and afar-field image sensor, configured for capturing image data objects in anear field of view associated with the near-field image sensor and a farfield of view associated with the far-field image sensor, respectively.In at least one example context, the multi-sensor imaging engine 100 isconfigured for capturing images for purposes of indicia reading atdifferent ranges, such as a close-range using a near-field image sensorand a far-range using a far-field image sensor.

As illustrated, the multi-sensor imaging engine 100 includes near-fieldimage capture optics 104A. The near-field capture optics 104A may beembodied by one or more lens(es) and/or other optical componentsconfigured to enable light to transverse through and interact with acorresponding image sensor, specifically the near-field image sensor102A. In this regard, the near-field image capture optics 104A maydefine a particular field of view that may be captured by a near-fieldimage sensor 102A. In some embodiments, the near-field image captureoptics 104A defines a near field of view associated with a first focalrange, such that objects located at and/or within a determinable offsetfrom the first focal range may be clear in images captured by thenear-field image sensor 102A.

Additionally as illustrated, the multi-sensor imaging engine 100includes far-field image capture optics 104B. The far-field imagecapture optics 104B may be embodied by one or more lens(es) and/or otheroptical components configured to enable light to transverse through andinteract with a corresponding image sensor, specifically the far-fieldimage sensor 102B. In this regard, the far-field image capture optics104B may define a second field of view that may be captured by thefar-field image sensor 102B. In some embodiments, the far-field imagecapture optics 104B defines a far field of view that is associated witha second focal range, such that objects located at and/or within adeterminable offset from the second focal range may be clear in imagescaptured by the far-field image sensor 102B. In some such embodiments,the near field of view is wider than the far field of view, such thatthe captured data represents more of the environment within view of themulti-sensor imaging engine 100. The far field of view may be narrowerthan the near field of view and focused on a further range to enableclearer capture of objects located at a greater range than objects thatcan be captured clearly in the near field of view. The physical layoutof illumination sources, image sensors can be changed in differentapplications.

In some example embodiments, the near-field imaging sensor 102A mayinclude a global shutter to provide enhanced motion tolerance. The nearfield imaging sensor 102A may use a large Field of View (FOV), the largeFOV enabling applications such as but not limited to optical characterrecognition (OCR), image reconstruction, machine learning etc. In someembodiments, the far field sensor 102B may include a rolling shutter.The far field image sensor 102B uses a small FOV to improve the samplingof far field. Additionally, each of the near-field image sensor 102A andthe far-field image sensor 102B may have an associated focus mechanism.The focus mechanism may include a focus scheme that controls movement ofone or more focus lenses along an optical axis direction of an imagesensor (102A or 102B). Towards this end, in some embodiments, the focusscheme may include one or more motors for example, stepper motors. Thefocus scheme may provide a plurality of discrete focus positions in eachfield of view and the motor may move the focus optics of a particularimage sensor to each of the discrete focus positions to exhibit thefocus mechanism. For example, in some example embodiments, to change thefocusing of the far field image sensor 102B, the corresponding motor maymove the associated focus optics of the far field imaging sensor 102B tothree discrete focus positions in the far field. The operation of eachof the focus mechanisms may be controlled by a processing component suchas the controller 20 of FIG. 1A or the processor 202.

In some embodiments, for example as illustrated, each image sensor (or asubset thereof) is associated with one or more components for producingan illumination configured for illuminating the field of view defined bythe image sensor. For example, as illustrated, the multi-sensor imagingengine 100 additionally comprises the near-field illumination source106A and corresponding near-field projection optics 108A. The near-fieldillumination source 106A may produce illumination pulses constituting anear-field illumination pulse train. That is, the activation of thenear-field illumination source 106A occurs for a time period and thenthe near-field illumination source 106A remains deactivated for a settime period before next activation. The near-field illumination source106A is configured to produce light in the optical axis direction of thenear-field projection optics 108A. This light is refracted through thenear-field projection optics 108A to produce a near-field illumination,which may be produced in a desired pattern based on the configurationand design of the near-field projection optics 108A. In this regard, theillumination produced by light exiting the near-field projection optics108A may illuminate a particular field of view, such as the near fieldof view capturable by the near-field image sensor 102A. It should beappreciated that in some embodiments, the near-field illumination source106A and/or near-field projection optics 108A may be designed such thatthe near field illumination specifically illuminates the near field ofview, and may affect the functioning of the far-field image sensor 102Bwithout negatively affecting the functioning of the near-field imagesensor 102A. For example, due at least in part to the close proximitybetween the components, reflected light may interact with the far-fieldimage sensor 102B and negatively affect the images created via far-fieldimage sensor 102B. In some example embodiments, the near-fieldillumination source 106A may produce the near-field illumination basedon one or more illumination pulses constituting a near-fieldillumination pulse train.

Similarly, the multi-sensor imaging engine 100 additionally comprisesthe far-field illumination source 106B and corresponding far-fieldprojection optics 108B. The far-field illumination source 106B producesfar-field illumination pulses constituting a far-field illuminationpulse train. The far-field illumination source 106B is configured toproduce light in the direction of the far-field projection optics 108B.This light is refracted through the far-field projection optics 108B toproduce a far-field illumination, which may be produced in a desiredpattern based on the configuration and design of the far-fieldprojection optics 108B. In this regard, the far-field illumination mayilluminate a particular field of view, such as the far field of viewcapturable by the far-field image sensor 102B. It should be appreciatedthat the far-field illumination source 106B and/or far-field projectionoptics 108B may be designed such that the far-field illuminationspecifically illuminates the far field of view without producingsufficient reflections to negatively impact the operations of thenear-field image sensor 102A and/or far-field image sensor 102B.

Additionally or alternatively, optionally in some embodiments, themulti-sensor imaging engine 100 further comprises an aimer illuminationsource 110. The aimer illumination source 110 is configured to producelight in the direction of the aimer projection optics 112. For example,the aimer illumination source comprises one or more laser diodes and/orhigh intensity LED(s) configured to produce sufficiently powerful and/orconcentrated light. The light is refracted through the aimer projectionoptics 112 to produce an aimer illumination, which may be produced in adesired pattern based on the configuration and design of the aimerprojection optics 112. In one example context, for purposes of barcodescanning for example, the aimer pattern may be produced as a laser linepattern.

The multi-sensor imaging engine 100 further comprises a protectivewindow 114. The protective window 114 comprises one or more opticalcomponents configured to enable produced light to exit the engine 100,and incoming light to be received through the image capture optics 104Aand 104B to interact with the corresponding image sensors 102A and 102B.In some contexts, the protective window 114 reflects at least a portionof the illumination projected by the far-field projection optics 108Band/or near-field projection optics 108A, and which may interact withthe image sensor(s) 102A and/or 102B through light leak or through thecorresponding image capture optics 104A and/or 104B. For example, atleast a portion of the near field illumination may be reflected towardsthe far-field image sensor 102B, and negatively affect the operation ofthe far-field image sensor 102B if triggered when an illumination pulseis occurring. In at least one example context, the far-fieldillumination source 106B produces light that is concentrated and/orotherwise sufficiently designed such that the far-field illuminationproduced by the far-field projection optics 108B is not sufficientlyreflected to negatively affect the near-field image sensor 102A.

It should be appreciated that, in other embodiments, a multi-sensorimaging engine may include any number of image capture optics, imagesensors, illumination sources, and/or any combination thereof. In thisregard, the imaging engine 100 may be extended to capture any number offield of views, which may each be associated with a correspondingilluminator designed for specifically illuminating a corresponding fieldof view. One or more of the illumination source(s) may negatively affectoperation of another illuminator. In such circumstances, when one suchillumination source is active, the negatively affected image sensor maybe activated between illumination pulses of the illumination source asdescribed herein. Such operation may be implemented for anycombination(s) of illumination source and image sensor.

In some embodiments, the multi-sensor imaging engine 100 includes one ormore processing components (e.g., a processor and/or other processingcircuitry) for controlling activation of one or more components of themulti-sensor imaging engine 100. For example, in at least one exampleembodiment, the multi-sensor imaging engine 100 includes a processorconfigured for timing the illumination pulses of the near-fieldillumination source 106A and/or far-field illumination source 106B,and/or controlling the exposing of the near-field image sensor 102Band/or far-field image sensor 102A. In some such contexts, the processoris embodied by any one of a myriad of processing circuitryimplementations, for example as a FPGA, ASIC, microprocessor, CPU,and/or the like. In at least some embodiments, the processor may be incommunication with one or more memory device(s) having computer-codedinstructions enabling such functionality when executed by theprocessor(s). In some embodiments, it should be appreciated that theprocessor may include one or more sub-processors, remote processors(e.g., “cloud” processors) and/or the like, and/or may be incommunication with one or more additional processors for performing suchfunctionality. For example, in at least one embodiment, the processormay be in communication, and/or operate in conjunction with, anotherprocessor within an imaging apparatus, for example the processor 202 asdepicted and described with respect to FIG. 2 .

FIG. 2 illustrates an example multi-sensor imaging apparatus, inaccordance with an example embodiment of the present disclosure.Specifically, FIG. 2 illustrates an example multi-sensor imagingapparatus 200. As illustrated, the multi-sensor imaging apparatus 200comprises an apparatus chassis 210 for housing the various components ofthe apparatus. In this regard, it should be appreciated that theapparatus chassis may be embodied in any of a myriad of chassis designs,using any of a myriad of materials, and/or the like, suitable toposition the various components of the multi-sensor imaging apparatus200 for operation. In at least one example context, the apparatuschassis 210 may be embodied as a handheld apparatus chassis, wearablechassis, and/or the like.

The multi-sensor imaging apparatus 200 comprises the multi-sensorimaging engine 100 as described above with respect to FIG. 1B. Themulti-sensor imaging apparatus 200 further comprises a processor 202.The processor 202 (and/or any other co-processor(s) and/or processingcircuitry assisting and/or otherwise associated with the processor 202)may provide processing functionality to the multi-sensor imagingapparatus 200. In this regard, the processor 202 may be embodied in anyone of a myriad of ways as discussed with respect to the controller 20of FIG. 1A.

In some example embodiments, the processor 202 is configured to providefunctionality for operating one or more components of the multi-sensorimaging apparatus 200. For example, the processor 202 may be configuredfor activating the far-field illumination source 106B, the near-fieldillumination source 106A, and/or the aimer illumination source 110.Additionally or alternatively, in some embodiments, the processor 202 isconfigured for activating the near-field image sensor 102A and/orfar-field image sensor 102B to expose the corresponding image sensor,and/or for reading out the captured data to generate an image based onthe data captured during exposure. Additionally or alternatively, insome embodiments, the processor 202 is configured to process thecaptured image(s), for example based on one or more image processingtask(s). In one such example context, the processor 202 is configured toperform an attempt to detect and decode visual indicia(s), such as 1Dand/or 2D barcodes, from a captured image. In this regard, the processor202 may be configured to utilize a visual indicia parsing algorithmand/or a visual indicia decoding algorithm to provide suchfunctionality.

Additionally or alternatively, optionally in some embodiments, themulti-sensor imaging apparatus 200 further include activation component206. The activation component 206 may be embodied in a myriad of ways asdiscussed with respect to the activation component 60 of FIG. 1A.

Additionally or alternatively, optionally in some embodiments, theimaging apparatus 200 further includes a display 208. The display 208may be embodied by a LCD, LED, and/or other screen device configured fordata provided by one or more components of the apparatus 200. Forexample, in some embodiments, the display 208 is configured forrendering a user interface comprising text, images, control elements,and/or other data provided by the processor 202 for rendering. In someembodiments, for example, the display 208 is embodied by an LCD and/orLED monitor integrated with the surface of the apparatus chassis 210 andvisible to an operator, for example to provide information decoded froma barcode and/or associated with such information decoded from abarcode. In one or more embodiments, the display 208 may be configuredto receive user engagement, and/or may transmit one or morecorresponding signals to the processor 202 to trigger functionalitybased on the user engagement. In some such embodiments, the display 208to provide user interface functionality embodying activation component206, for example to enable an operator to initiate and/or terminatescanning functionality via interaction with the user interface.

Additionally or alternatively, optionally in some embodiments, thedual-imaging apparatus 200 further includes a memory 204. The memory 204may provide storage functionality, for example to store data processedby the multi-sensor imaging apparatus 200 and/or instructions forproviding the functionality described herein. In some embodiments, theprocessor 202 may be in communication with the memory 204 via a bus forpassing information among components of the apparatus, and/or forretrieving instructions for execution. The memory 204 may be embodied ina myriad of ways discussed with reference to the controller 20 of FIG.1A. The memory 204 may be configured to store information, data,content, applications, instructions, or the like, for enabling theimaging apparatus 200 to carry out various functions in accordance withsome example embodiments. In some embodiments, the memory 204 includescomputer-coded instructions for execution by the processor 202, forexample to execute the functionality described herein and/or inconjunction with hard-coded functionality executed via the processor202. For example, when the processor 202 is embodied as an executor ofsoftware instructions, the instructions may specially configure theprocessor 202 to perform the algorithms and/or operations describedherein when the instructions are executed. Non-limiting examplesimplementations of the multi-sensor imaging engine 100 and multi-sensorimaging apparatus 200 are described in U.S. patent application Ser. No.16/684,124 filed Nov. 14, 2019, titled “INTEGRATED ILLUMINATION-AIMERIMAGING APPARATUSES,” the contents of which are incorporated byreference in its entirety herein. It should be appreciated that one ormore of such components may be configurable to provide the illuminationsynchronization as described herein.

In some example embodiments of the present disclosure, processor 202 andmemory 204 may together be embodied as an imaging control apparatus oran illumination control apparatus and may therefore be fixed ordetachably coupled with the imaging apparatus 200 or may be partially orcompletely outside the imaging apparatus 200. In some embodiments, theimaging control apparatus may be embodied as an integrated circuit thatis operatively coupled with the imaging apparatus 200.

FIG. 3 illustrates a visualization of the field of views capturable byan example multi-sensor image apparatus. For example, as illustratedFIG. 3 depicts the near field of view 302 and the far field of view 304capturable by the multi-sensor imaging apparatus 200. As illustrated,the near field of view 302 is broader than the far field of view, suchthat more of the environment may be captured within the near field ofview 302 than the far field of view 304.

Further, as illustrated, the far field of view 304 extends further thanthe near field of view 302. In this regard, the narrow nature of the farfield of view 304 may enable capture of more detailed representations ofa particular portion of the environment as compared to the near field ofview 302. In some embodiments, the near field of view 302 and far fieldof view 304 are capturable by corresponding near field image sensor anda corresponding far field image sensor of the multi-sensor imagingapparatus 200. The near field of view 302 may be associated with a nearfocal range at a particular distance from the corresponding image sensorin the multi-sensor imaging apparatus 200. Additionally oralternatively, the far field of view 304 may be associated with a farfocal range at another distance from the corresponding image sensor inthe multi-sensor imaging apparatus 200. In this regard, the near fieldfocal range may be closer than the far-field focal range, such thatobjects further from the multi-sensor imaging apparatus 200 are inbetter focus when captured via the far-field image sensor, allowing foran extended range as compared to the near field image sensor.

The multi-sensor imaging apparatus 200 may be configured for providingan illumination specifically for illuminating each of the field of views302 and 304. In this regard, an illumination source may be specificallydesigned to match the field of view of a corresponding image sensor,such that the illumination appropriately illuminates the correspondingfield of view without overfill or underfill. Utilizing anotherillumination source to produce an illumination and capturing during thenon-corresponding image sensor during the illumination, may result inoverfilling (e.g., when capturing using a far-field image sensor duringa near-field illumination pulse), and/or underfilling (e.g., whencapturing using a near-field image sensor during a far-fieldillumination pulse) that may affect the quality of the data in thecaptured image, such as due to having too much illumination and/or notenough as described. For example, FIG. 4 illustrates a visualization ofa near-field illumination produced by a multi-sensor imaging apparatus,for example the multi-sensor imaging apparatus 200, in accordance withan example embodiment of the present disclosure. In this regard, thenear-field illumination 402 may be produced so as to substantially orentirely illuminate the near field of view 302. The near-fieldillumination 402 may be produced in accordance with an illuminationpattern that sufficiently illuminates the entirety of the near-field ofview 302 for capturing.

FIG. 5 illustrates a visualization of a far-field illumination producedby an example multi-sensor imaging apparatus, for example themulti-sensor imaging apparatus 200, in accordance with an exampleembodiment of the present disclosure. In this regard, the far-fieldillumination 404 may be produced so as to substantially or entirelyilluminate the far field of view 304. The far-field illumination 504 maybe produced in accordance with an illumination pattern that sufficientlyilluminates the entirety of the far field of view 304 for capturing by acorresponding far-field image sensor. The far-field illumination 504 mayilluminate only a percentage of the near-field of view 302, for examplea center percentage (e.g., 25%, 50%, or the like) of the near field ofview 302. In this regard, the activation of the far-field illuminationmay be problematic for capturing sufficient images of certain visualindicia, such as those that extend past the boundaries of the far-fieldof view 304 at a particular distance. Accordingly, utilizing theappropriate illuminator for each image sensor while minimizing flickerand minimizing operational time is desirable to increase the likelihoodand efficiency of successful visual indicia detecting and decoding.

FIG. 6 illustrates a timing diagram 600 associated with operationalfunctionality of an example multi-sensor imaging system, in accordancewith an example embodiment. The timing diagram 600 illustratesactivation and deactivation timings for the various components (e.g.,but not limited to a near-field illumination source, a near-field imagesensor, a far-field illumination source, a far-field image sensor, afocusing mechanism) of the multi-sensor imaging apparatus 200. Severalindividual processes associated with the imaging system 10/imagingapparatus 200 are illustrated with the aid of pulses in the timingdiagram 600 of FIG. 6 . The vertical expanse of a pulse in the timingdiagram does not necessarily specify the pulse's amplitude. According tosome example embodiments, each pulse in the timing diagram 600 may bedefined by a length of active time of an associated component/processfollowed by a length of inactive time of the associatedcomponent/process. Each pulse may have a corresponding period which maybe defined as the time duration for which the amplitude of the pulseremains non-zero. The period of a pulse may begin at a start timeinstance (pulse start time) and end at an end time instance (pulse endtime). As used herein, the term start time period of a period of a pulsemay refer to a time period of a threshold duration starting from a pulsestart time, where the threshold duration may have a configurable value.In an example, the threshold duration may be zero and as such, the starttime period of a period and the pulse start time may refer to the sameinstance in time. Similarly, the term end time period of a period of apulse may refer to a time period of a threshold duration ending at apulse end time, where the threshold duration may have a configurablevalue. In at least one example context, the threshold duration may bezero and as such, the end time period of a period and the pulse end timemay refer to the same instance in time. In some example embodiments, therespective threshold durations may be configurable as per one or moreperformance parameters of the controller 20 and/or the imaging engine100.

As illustrated in the timing diagram 600, some pulses associated with aparticular operation of a particular component of the imaging system10/imaging apparatus 200 may be temporally aligned, partially or fullyoverlapped, or may not overlap with one or more other pulses associatedwith one or more operations of another component of the imaging system10/imaging apparatus 200. As an example, a start of the near fieldillumination pulse 602A is temporally aligned with the start of thepulse 604 associated with exposure of the near-field image sensor (alsoreferred to as near-field exposure pulse 604). As another example, thenear field illumination pulse 602A may not overlap with the pulse 606associated with the read-out of the near-field image sensor (alsoreferred to as near-field read-out pulse 606). As another example, thepulse 614A associated with exposure of the far-field image sensor (alsoreferred to as far-field exposure pulse 614A) overlaps with thenear-field read-out pulse 606.

Executable instructions corresponding to the operations illustrated inthe timing diagram 600 may be utilized by the imaging system/imagingapparatus to perform smooth execution of one or more imaging or imageprocessing tasks. For example, each image sensor activation may comprisetwo steps to capture a corresponding image: exposing the image sensorand readout from the image sensor. In this regard, it should beappreciated that the processor 202, for example, may be configured toenable activation of the various components based on the timing diagram.According to some example embodiments, the image sensors (102A, 102B)may be operated in a manner such that the exposure period of thefar-field image sensor 102B is adjusted or accommodated into theillumination pulse train of the near-field illumination source 106A.Such modification of the illumination pulse train of the near-fieldillumination source 106A to accommodate the exposure period of thefar-field image sensor 102B may be accomplished by various ways, someexamples of which will be discussed with reference to FIGS. 8-10 .

As illustrated, the timing diagram 600 includes a near-fieldillumination pulse train 602 used by the near-field illumination source106A for producing a near-field illumination. The near-fieldillumination pulse train 602 comprises a plurality of illuminationpulses such as illumination pulse 602A, 602B, 602C, 602D, and 602E. Itshould be noted that in the unmodified form, the near-field illuminationpulse may only comprise illumination pulses similar to illuminationpulse 602A which are produced at a certain fixed frequency. Illuminationpulses similar to the additional illumination pulses 602B-602E may beadded by the controller 20 or processor 202 to accommodate the exposureperiod 614 of the far-field image sensor 102B, in the near-fieldillumination pulse train 602, to alleviate the illumination problemsassociated with the multi sensor imaging apparatus 200/system 10. Inthis regard, each near-field illumination pulse may be defined by alength of active time (e.g., near-field illumination source 106Aon-time), followed by a length of inactive time (e.g., near-fieldillumination source 106A off-time). In an example context, themulti-sensor imaging apparatus 200 may be configured to periodicallyproduce the near-field illumination pulses 602A with an on-time of 1.5milliseconds (“ms”), followed by an off-time of 14.5 ms. In this regard,each illumination pulse 602A may begin, last for 1.5 ms, andsubsequently end before another illumination pulse 602A begins after14.5 ms elapses. To avoid occlusion, only one illumination pulse 602A isshown in the near-field illumination pulse train 602. However, it may becontemplated that as per the example embodiments described herein, thenear-field illumination pulse train 602 in its unmodified form comprisesa plurality of such illumination pulses 602A. The near-fieldillumination source 106A may produce the additional illumination pulses602B-602E in a similar manner as described above with same or differenton-times and off-times. Each of the illumination pulses 602A-602E mayextend in time domain for a duration referred to as an illuminationperiod. In the example embodiment described above, for example, eachillumination pulse 602A may have an illumination period equal to 1.5milliseconds. The illumination period of an illumination pulse may beginat a first time instance and end at a second time instance. As such, thefirst time instance may correspond to the illumination pulse start timeof the illumination pulse and the second time instance may correspond tothe illumination pulse end time of the illumination pulse.

In some example embodiments, the near-field image sensor 102A andfar-field image sensor 102B may each be activated while the near-fieldillumination is produced. As illustrated, the exposure pulse 604 of thenear-field image sensor may be fully or substantially aligned with thenear-field illumination pulse 602A of the near-field illumination pulsetrain 602. That is, the exposure of the near-field image sensor duringthe exposure period 604 may begin simultaneously with a start timeperiod of the near-field illumination pulse 602A of the near-fieldillumination pulse train 602. In some example embodiments, an end timeperiod of the exposure period 604 may extend beyond the end time periodof the near-field illumination pulse 602A of the near-field illuminationpulse train 602. For example, as illustrated, the near-field imagesensor exposure begins at the rising edge of the exposure pulse 604,which is aligned with the rising edge of the first near-fieldillumination pulse 602A. The exposure of the near-field image sensor102A ends at a time instance that is beyond the falling edge of thefirst near-field illumination pulse 602A. In this regard, the near-fieldimage sensor 102A is exposed during the entirety (or near entirety) ofthe first near-field illumination pulse 602A, maximizing the likelihoodof capturing sufficient data to enable successfully completing an imageprocessing task such as barcode scanning.

It should be appreciated that, in some embodiments, the illuminationpulse may occur during any point in the exposure of an image sensor whenit is desired that the image sensor be exposed during the illuminationpulse. For example, in a circumstance where the near-field image sensor102A is to be exposed during a near-field illumination pulse, theexposure may begin before the illumination pulse or the illuminationpulse may occur at a later time during the exposure. As one suchexample, in the context where the near-field image sensor 102A isassociated with a 4.5 ms exposure time value, and each near-fieldillumination pulse lasts 1.5 ms, the exposure of the near-field imagesensor 102A could begin at any time between the beginning of theillumination pulse and 3 ms before the illumination pulse start time,such that the entirety of the illumination pulse occurs during theexposure. It should be appreciated that the specific timing may differfor any combination of differently configured image sensor(s) and/orillumination source(s).

As illustrated, the near-field image sensor 102A is subsequently readout in pulse 606 to generate and/or process a corresponding image (e.g.,a first near-field image) in pulse 608. Parallel to the start of theread-out from the near-field image sensor 102A in pulse 606, theexposure of the far-field sensor 102B may begin at pulse 614.Thereafter, with end of the exposure of the far field sensor 102B inpulse 614, the read-out from far-field sensor may begin at pulse 616 togenerate and/or process a corresponding image (e.g., a first far-fieldimage) in pulse 618.

It should be noted that in some example embodiments, a start time periodof the exposure period of the pulse 614 may be fully or substantiallyaligned with a start time period of the read-out period of the pulse606. Further, an end time period of the exposure period of the pulse 614may be fully or substantially aligned with a start time period of theread-out period of the pulse 616.

The timing of the illumination pulse(s), corresponding exposure,read-out and/or processing may be determined in any one of a myriad ofways. For example, in at least one example embodiment, the timings foractivation of the illumination pulse(s) and/or image sensor exposure(s)may be predetermined and/or hard coded for execution by one or moreassociated processor(s). Additionally or alternatively, in someembodiments, a timing offset until a next illumination pulse may bedetermined based on the pulse frequency for the produced illumination,and/or a start time of the illumination pulse (e.g., a time at which afirst illumination pulse was produced). The exposure of one or moreimage sensors may be appropriately timed based on a known and/ordeterminable current time, an illumination pulse frequency, thedetermined offset, and/or the exposure time value for the image sensorto be exposed. For example, based on such data, exposure of an imagesensor may be triggered such that the image sensor remains exposed forthe entirety of an illumination pulse in some circumstances, and/orremains exposed entirely or partially between illumination pulses inother circumstances.

Each illumination source is utilized to illuminate a desired field ofview for capture by corresponding image sensor(s), increasing thelikelihood of successfully completing an image processing task such asbarcode scanning.

FIG. 7 illustrates a flowchart depicting example operations of a process700 for illumination control in a multi-imager environment, inaccordance with an example embodiment of the present disclosure. FIG. 7will be described in conjunction with the timing diagram 600 illustratedin FIG. 6 . Process 700 may be implemented by the imaging system 10 orimaging apparatus 200 described with reference to FIG. 1A and FIG. 2 .The process 700 includes at 702, operating, by the controller20/processor 202, a first illumination source based on a firstillumination pulse train. The first illumination source can correspondto a light source associated with a near field sensor. As an example,the first illumination source may be the near-field illumination source106A described in reference to FIG. 1B-FIG. 2 . The first illuminationsource may illuminate a near-field of view of the near-field imagesensor in accordance with the first illumination pulse train. The firstillumination pulse train may correspond to the near-field illuminationpulse train 602 illustrated in the timing diagram of FIG. 6 . In someexample embodiments, the first illumination pulse train may have aconstant pulse frequency of around 60-90 Hz to produce short, brightpulses of illumination. In some sensitive applications, the pulsefrequency may be set to a constant value beyond 90 Hz.

The process 700 further includes at 704, determining, by the controller20/processor 202, a first exposure period of a second image sensor. Insome example embodiments, the second image sensor may be the far-fieldimage sensor 102B and as such, the first exposure period may correspondto an exposure period of the far-field sensor 102B. Illumination andexposure of the second image sensor may be controlled or caused by acontrol or processing medium such as the controller 20 or processor 202.Accordingly, the first exposure period of the second image sensor may bepredetermined and/or hard coded for execution by one or more associatedprocessor(s). In some example embodiments, the exposure period may bedynamically computed based on one or more imaging parameters associatedwith the second image sensor.

The process 700 further includes at 706, modifying, by the controller20/processor 202, one or more characteristics of the first illuminationpulse train to accommodate the first exposure period of the second imagesensor. By modifying the one or more characteristics such as pulsefrequency of the first illumination pulse train, the process 700provides an efficient measure for inhibiting the “illumination spill”from the far-field image sensor into the near-field image sensor andvice versa. The modification of the one or more characteristics of thefirst illumination pulse train may be performed with the objective ofreducing illumination interference amongst the image sensors of theimaging system. Accordingly, one or more characteristics of the firstillumination pulse train may be modified in a myriad of ways. In someexample embodiments, one or more additional illumination pulses may beadded or inserted into the first illumination pulse train to avoid theillumination interference with exposure of the second image sensor, adetailed description of which has been provided with reference toprocesses 706A and 706B of FIGS. 8 and 9 respectively. Additionally oralternatively, in some example embodiments, the timing delay between apair of temporally subsequent illumination pulses of the firstillumination pulse train may be increased to avoid the illuminationinterference with exposure of the second image sensor, a detaileddescription of which has been provided with reference to process 706C ofFIG. 10 .

The process 700, at 708 includes operating, by the controller20/processor 202, the first illumination source associated with thefirst image sensor, based on the modified first illumination pulsetrain. Thus, the controller 20/processor 202 controls subsequentactivation of the near-field illumination source based on the modifiednear-field illumination pulse train. The exposure of the near-fieldimage sensor is accordingly aligned with the illumination pulses of themodified near-field illumination pulse train to perform the imagecapture by the near-field image sensor. Since the modified near-fieldillumination pulse train is generated considering the exposure period ofthe far-field image sensor, the likelihood of an illumination spillamongst the two sensors is reduced or in some cases eliminated.Therefore, the process 700 provides an efficient measure to operate amulti-sensor imaging system/apparatus. Accordingly, an apparatusexecuting or utilizing the process 700 results in improvements inimaging and/or subsequent image processing tasks.

FIG. 8 illustrates a flowchart depicting example operations of a process706A for modifying one or more characteristics of the first illuminationpulse train to accommodate a first exposure period of the second imagesensor of an example multi-sensor imaging system, in accordance with atleast one example embodiment of the present disclosure. In some exampleembodiments, the process 706A may be triggered in scenarios whereillumination synchronization is required along with flicker control orelimination.

Process 706A includes at 802, determining, by the controller20/processor 202, a start time period and an end time period of thefirst exposure period of the second image sensor. As describedpreviously, the second image sensor may be the far-field image sensor102B. As such, the controller 20/processor 202 may determine the metesand bounds of the exposure period of the far field image sensor.Furthermore, as discussed with reference to step 704 of FIG. 7 , thefirst exposure period of the second image sensor may be predeterminedand/or hard coded for execution by one or more associated processor(s).In some example embodiments, the exposure period may be dynamicallycomputed based on one or more imaging parameters associated with thesecond image sensor. The controller 20/processor 202 may obtain dataregarding the exposure period of the far field image sensor from any ofthe above-mentioned sources and determine the start-time period and endtime period of the exposure period.

At step 804, process 706A includes generating, by the controller20/processor 202, at least one additional illumination pulse for thefirst illumination pulse train of the first image sensor. The at leastone additional illumination pulse may be generated for inserting it intothe first illumination pulse train. Accordingly, process 706A furtherincudes at 806, inserting, by the controller 20/processor 202, the atleast one additional illumination pulse into the first illuminationpulse train such that the start time period and/or an end time period ofthe illumination period of the at least one additional illuminationpulse is aligned with the start time period and/or an end time period ofthe first exposure period of the second image sensor. That is, the atleast one additional illumination pulse may be added or inserted intoone or more “don't care regions” of the pulse corresponding to theexposure period of the second image sensor. The “don't care regions” maycorrespond to such portions of the exposure period in which an object ora portion thereof is not captured. As discussed, the second image sensormay be a far field image sensor and in usual scenarios an initial windowand a terminal window associated with the pulse corresponding to theexposure period of the far field image sensor may not be associated withcapture of an object because the object is usually captured within acenter window of the exposure period of the far field image sensor.Thus, in the example illustrated herein, the initial and terminalwindows of the exposure period may correspond to the don't care regions.It may however be contemplated that additionally or alternatively, anyother portion of the exposure period may as well be defined as the don'tcare region within the scope of this disclosure.

As shown in FIG. 6 , the one or more additional illumination pulses 602Band 602E (shown in fine dotted lines) are generated and inserted intothe near-field illumination pulse train 602 such that a start timeperiod of the illumination period of the illumination pulse 602B isaligned with a start time period of the exposure period 614A of thefar-field image sensor, and a start time period of the illuminationperiod of the illumination pulse 602E is aligned with a start timeperiod of the exposure period 614B of the far-field image sensor.

FIG. 9 illustrates a flowchart 706B depicting example operations ofanother process for modifying one or more characteristics of the firstillumination pulse train to accommodate the first exposure period of thesecond image sensor of an example multi-sensor imaging system, inaccordance with at least one example embodiment of the presentdisclosure. In some example embodiments, the process 706B may betriggered in scenarios where illumination synchronization is requiredalong with flicker elimination.

Process 706B includes at 902, determining, by the controller20/processor 202, an autofocus period of the second image sensor. Duringoperation of the second image sensor for imaging in the far field, it isrequired that the image sensor be moved to one of several focuspositions. The shift from an initial position of the image sensor(and/or associated optics) to one of the focus positions occurs duringan autofocus period. The autofocus period may be predefined and storedin a memory of the imaging engine or may be dynamically computed basedon one or more imaging parameters. In either case, the controller20/processor 202 may obtain or otherwise calculate the autofocus period.

At step 904, process 706B includes generating, by the controller20/processor 202, at least one additional illumination pulse for thefirst illumination pulse train of the first image sensor. The at leastone additional illumination pulse may be generated for inserting it intothe first illumination pulse train. Accordingly, process 706B furtherincudes at 906, inserting, by the controller 20/processor 202, the atleast one additional illumination pulse into the first illuminationpulse train such that illumination of the first image sensorcorresponding to the at least one additional illumination pulsetemporally overlaps the autofocus period of the second image sensor.That is, the at least one additional illumination pulse may be added orinserted into the first illumination pulse train in positions alignedwith a period of motor movement of the second image sensor.

As shown in FIG. 6 , the one or more additional illumination pulses 602D(shown in thick dotted lines) are generated and inserted into thenear-field illumination pulse train 602 such that the illuminationperiod of the illumination pulse 602D overlaps the autofocus motor movepulse 610.

FIG. 10 illustrates a flowchart depicting example operations of anotherprocess 706C for modifying one or more characteristics of the firstillumination pulse train to accommodate the first exposure period of thesecond image sensor of an example multi-sensor imaging system, inaccordance with at least one example embodiment of the presentdisclosure. Process 706C includes at 1002, determining, by thecontroller 20/processor 202, a start time period and an end time periodof the first exposure period of the second image sensor. As describedpreviously, the second image sensor may be the far-field image sensor102B. As such, the controller 20/processor 202 may determine the metesand bounds (start time period and end time period) of the exposureperiod of the far field image sensor. Furthermore, as discussed withreference to step 704 of FIG. 7 , the first exposure period of thesecond image sensor may be predetermined and/or hard coded for executionby one or more associated processor(s). In some example embodiments, theexposure period may be dynamically computed based on one or more imagingparameters associated with the second image sensor. The controller20/processor 202 may obtain data regarding the exposure period of thefar field image sensor from any of the above mentioned sources anddetermine the start-time period and end time period of the exposureperiod.

Process 706C further includes at 1004, determining, by the controller20/processor 202, a pair of temporally subsequent illumination pulses ofthe first illumination pulse train that are in closest temporal vicinityof the first exposure period of the second image sensor. The controller20/processor 302 may determine the start time instance and end timeinstance of the exposure period of the far field image sensor. Thecontroller 20/processor 302 may map the determined start time instanceand end time instance of the exposure period onto the near-fieldillumination pulse train to determine a pair of temporally subsequentillumination pulses in the near-field illumination pulse train that arein closest vicinity of the determined start time instance and end timeinstance of the exposure period, respectively, on a time axis.

Process 706C further includes at 1006, increasing, by the controller20/processor 202, a timing delay between the qualified pair oftemporally subsequent illumination pulses of the first illuminationpulse train such that one of the start time period or the end timeperiod of the first exposure period is aligned with a respective one ofa start time period or an end time period of the increased timing delay.As is illustrated in the example timing diagram 1100 of FIG. 11 ,illumination pulse pair 1104, 1106 and illumination pulse pair 1108,1110 of the near-field illumination pulse train may be selected as thequalified pair of temporally subsequent illumination pulses that are inclosest vicinity to the start time instance and end time instance of theexposure period 1112. Accordingly, the controller 20/processor 302 mayincrease a timing delay between the illumination pulses (1102-1110) suchthat the start time period and/or the end time period of the exposureperiod 1112 is aligned with a respective one of a falling edge of theillumination pulse 1104 and a rising edge of the illumination pulse1106, respectively. The falling edge of the illumination pulse 1104 maybe within a threshold delay from the start time period of the exposureperiod 1112 and the rising edge of the illumination pulse 1106 may bewithin another threshold delay from the end time period of the exposureperiod 1112. Similar modifications to other pulses of the exposureperiod may be made to align with a corresponding pair of illuminationpulses. The time duration between the rising edge of the illuminationpulse 1104 and the falling edge of the illumination pulse 1106 definesthe increased timing delay. Thus, as is illustrated in the modified nearfield illumination pulse train of FIG. 11 , the start time period andthe end time period of the exposure period 1112 of the far-field imagesensor is aligned with a respective one of a start time period or an endtime period of the increased timing delay.

FIGS. 12A and 12B illustrate an example workflow of a symbol decodingprocess executed by an example multi-sensor imaging system, inaccordance with at least one example embodiment of the presentdisclosure. In some example embodiments, the imaging system 10 and/orthe imaging apparatus 200 may include or be a part of an exemplarysymbol reading device such as an indicia reader. Processes 1200A, 1200B,and 1200C as illustrated in FIGS. 12A, 12B, and 12C provide a symboldecoding method that includes various aspects of the method 700. Asymbol reader having multiple image sensors, when implementing theprocesses 1200A, 1200B, and 1200C is able to mitigate the problemsarising out of illumination spill as well as flicker and is thus able toprovide error free or reduced error capture of images of the symbol.This results in faster and efficient decoding of the symbol. Furtheradvantages of the workflow will become evident through the followingdisclosure of the workflow.

Some or all the steps of processes 1200A, 1200B, and 1200C may becarried out by appropriate data processing means and control means. Forexample, in some example embodiments, the processes 1200A, 1200B, and1200C may be carried out by a controller or one or more processors ofthe symbol reader. In some example embodiments, the controller of thesymbol reader may be embodied in a manner similar to that described withreference to controller 20 of the imaging system 10.

The process 1200A is triggered upon receipt of an input from a user onthe activation component 206 of the imaging apparatus 200. In response,process 1200A begins at 1202 by turning on the aimer as an indicator. Asdescribed in reference to FIG. 2 , the aimer illumination source 110 andthe aimer projection optics 112 may together produce the aimer as adesired pattern. Next, at 1204, the process 1200A includes turning onthe near-field illumination. The near-field illumination may be producedin a variety of ways, for example as discussed previously in thedisclosure. In some example embodiments, the near-field illumination isproduced according to a near-field illumination pulse train having afixed pulse frequency. The individual near-field illumination pulses maybe of short durations such as 1.5 ms.

The exposure of the near-field image sensor begins at 1206 substantiallysimultaneously with the activation of the near-field illuminationsource. In some example embodiments, the near-field image sensor mayinclude a global shutter and may have a large field of view. In someexample embodiments, the near-field image sensor may include a rollingshutter. Subsequently, at 1208, the process 1200A may includetransferring the data from the near field image sensor to capture afirst near field image. That is, the charges may be read-out toconstruct an image frame captured by the near-field image sensor.

Parallel to step 1208, at 1210, the process 1200A includes starting theexposure of the far field image sensor in the far field. In some exampleembodiments, the far-field image sensor may include a rolling shutterand may have a narrow field of view in comparison to the near-fieldimage sensor. After the exposure period of the far-field image sensorhas lapsed, the data transfer from the far-field image sensor may beginat 1212 to capture a first far-field image.

At 1214, upon capture of the first near-field image, process 1200Aincludes processing the first near-field image and starting a firstdecode run. The first near-field image is processed to get a distanceestimation of a target symbol in the image. Towards this end, anysuitable image processing-based distance estimation technique (forexample, but not limited to using the parallax-based technique or thedisparity in sharpness of images from the near-field image sensor andthe far field image sensor) may be utilized. For example, as a binarytest, it may be determined from the decoding results of the firstdecoding run, whether the target symbol was successfully captured or notin the first near-field image. The results of distance estimation may beused to decide whether the first far-field image is to be used fordecoding the symbol instead of the first near-field image. In examplescenarios where the target symbol is located beyond a maximum imagingrange of the near-field image sensor, the captured first near-fieldimage frame may not be indicative of the target symbol with acceptablelevels of clarity, brightness, contrast etc. As such, the near-fieldimaging may not be an appropriate means for decoding the symbol. In suchcases, the far-field image sensor may be relied upon to attempt asuccessful decode.

The process 1200A at 1216 includes, determining whether the symbol wassuccessfully decoded in the first decoding run. If the symbol issuccessfully decoded from the first near-field image, processing of thefirst far-field image may not be required and the control of stepspasses to step 1246 of FIG. 1200C where the decoded symbol may be outputby the symbol decoder. However, if at 1214 the symbol is notsuccessfully decoded by the symbol decoder, the process 1200A includesat 1218, moving the imaging engine and thereby the far-field imagesensor to a corresponding focus position. The movement to thecorresponding focus position includes determining the particular focusposition from a set of focus points based on the distance estimated instep 1214. The focus positions of an image sensor may be defineddiscretely as discrete steps to be traversed by a focus motor of theimagine engine. Subsequent to the movement of the imaging engine at1218, the control of steps passes to two parallel flows illustrated inprocess 1200B of FIG. 12B.

Process 1200B includes a first flow comprising steps 1220-1232 aimed atprocessing and imaging using the far-field image sensor and a secondflow comprising steps 1234-1242 aimed at imaging using the near fieldimage sensor. In some example embodiments, the second flow comprisingsteps 1234-1242 may be skipped in one or more iterations of theprocesses 1200A, 1200B, and 1200C.

Process 1200B includes at 1220, processing a far-field image (in thiscase the first far-field image) and starting the second decoding run.The first far field image may be processed to decode the target symboland alongside other parameters of the image may be obtained by theprocessing. The other parameters may be such as brightness of the firstfar-field image. Using these parameters, one or more sensor parametersof the far-field image sensor to be adjusted may be determined.Subsequently, at 1222 it is determined whether the symbol issuccessfully decoded in the second decoding run. If the result of thecheck at 1222 is positive (yes), the control of steps passes to step1246 of FIG. 1200C where the decoded symbol may be output by the symboldecoder. However, if at 1222 the symbol is not successfully decoded bythe symbol decoder, the control of steps passes to 1224 where it isdetermined whether illumination in the far-field is required or not.Such a determination may be made for example by any suitable imageprocessing technique on the first far-field image. If it is determinedthat far-field illumination is required, the far-field illuminationsource may be turned on at 1226 and control may pass to step 1228.However, if far-field illumination is not required, control may directlypass to step 1228. At 1228, the exposure of the far-field sensor beginswith or without illumination in the far-field, as the case may be.Subsequently, the transfer of data from the far-field image sensor maybe completed at 1230 to obtain a second far-field image. The secondfar-field image may be processed at 1232 and the third decoding run isattempted. Next, the control passes to step 1244 of process 1200Cillustrated in FIG. 7C.

In the parallel second flow of process 1200B, upon the determinationthat the symbol cannot be decoded successfully by the symbol decoder,the near-field illumination pulses are modified at 1234 to accommodateone or more exposure periods of the far-field image sensor. Modificationof the near-field illumination pulses may be achieved by modifying thenear-field illumination pulse train in a myriad of ways as discussedwith reference to FIGS. 8-10 . Subsequently, at 1236, the near-fieldillumination is started as per the modified near-field illuminationpulses and at 1238 the near-field image sensor may be exposed in thenear-field. Illumination and exposure of the near-field image sensorpost modification of the illumination pulses may be achieved in a mannersimilar to that described at steps 1204 and 1206 respectively. At 1240,the process 1200B includes starting the data transfer of the near-fieldimage sensor to capture a second near-field image. At 1242, the secondnear-field image may be processed, and the fourth decoding run may beattempted by the symbol decoder. Next, the control passes to step 1244of process 1200C illustrated in FIG. 7C.

At 1244, it is determined whether the symbol is decoded in any one ofthe third decoding run at 1232 or the fourth decoding run 1242. If thesymbol decoder is able to successfully decode the target symbol from anyone of the second far-field image or second near-field image, thecontrol of steps passes to 1246 where the decoded symbol is output bythe symbol decoder. However, if at 1244 it is determined that the symbolis not successfully decoded by the symbol decoder, control passes to1248 where it is determined whether there remains any focus positionthat is not yet visited. That is, the process 1200C includes determiningif amongst the focus positions of the far-field image sensor, there isany focus position from where imaging in the far-field is not yetperformed in any of the iterations. If there remains no such focusposition from where imaging in the far-field is not yet performed (thatis all focus positions have been visited), it is concluded that thetarget symbol is out of an imaging range of the symbol decoder or thereis no target symbol in the imaged field of view. Accordingly, at 1250 anerror message may be output indicating that the target symbol is notdecodable by the symbol decoder. If, however, at 1248 it is determinedthat there remains one or more focus positions that are not yet visited,control passes to 1252 where the imaging engine is moved in thefar-field to the corresponding position not yet visited. The movement ofthe imaging engine may be performed in a manner similar to the onedescribed with reference to step 1218 of FIG. 12B. The movement to afocus position may be scheduled in an ascending order (i.e. moving froma nearer-focus position to a farther-focus position amongst the discretefocus positions of the far-field image sensor). Subsequently, thecontrol returns to the two parallel flows of process 1200B at steps 1220and 1234.

In this way, the exemplar workflow illustrated in FIGS. 12A-12C may beutilized to perform symbol decoding by the symbol decoder, whereby owingto the improved illumination control provided by modification of thenear-field illumination pulses (pulse train), the likelihood ofsuccessfully decoding the target symbol from the near-field image andfar-field image is increased significantly. Such an improvement in thedecoding process brings about an improvement in the overallfunctionality of the symbol decoder device itself.

Although the exemplar workflow illustrated in FIGS. 12A-12C has beendescribed considering an end application as symbol decoding, it may becontemplated that within the scope of this disclosure, other endapplication tasks utilizing dual or multiple image sensors (and therebymultiple illumination sources) may as well be modified to benefit fromthe improved illumination control and synchronization framework providedherein. That is, in no way should the scope of the disclosure be limitedto symbol decoders alone and suitable modifications may be made toextend the illumination control framework to similar end use cases suchas multi-camera based mobile phones. In some example contexts, themulti-image sensor device may be embodied as a smartphone having atleast two cameras. The cameras may have a same or separate illuminationsource associated with each of them. At least one camera in thesmartphone may be considered as a primary camera which is associatedwith image capture in bright, well lit, as well as low lit scenarios.The image quality of such cameras may be directly associated with themegapixel (MP) strength and as such in some example embodiments, theprimary camera may have 12, 24, 48 or 64 MP. One or more other camerasin the smartphone may be considered as secondary cameras associated withone or more image enhancement functions. For example, the smartphone mayhave a telephoto lens supporting ultra-zoom options. In some exampleembodiments, the telephoto lens may support a zoom factor that rangesbetween 2× to 10×. In some more advanced embodiments, the smartphone mayhave an ultra-wide angle lens for enhancing the field of view of thesmartphone. Additionally or optionally, in some example embodiments, thesmartphone may include a depth sensor to measure the depth of backgroundsubjects in comparison with primary subjects in the field of view. Oneor more cameras of the smartphone may have a different illuminationrequirement to support universal imaging capabilities for thesmartphone. For example, while the primary camera may requireillumination flash for imaging in low lit scenarios, the monochrome lensof the smartphone may witness a spike in the brightness during imagingin the same pulse. As such, the resultant image may be compromised interms of one or more imaging parameters.

Example embodiments described herein help in alleviating the aforesaidproblems by providing an effective solution aimed at synchronizing theillumination for the multiple cameras in the smartphone. Particularly,as is illustrated in FIGS. 6-12C the exposure of one or more cameras maybe designed or adjusted to overlap or lie outside the exposure of one ormore other cameras, as the requirement may be. Since the exampleembodiments also provide an adaptive process for illuminationsynchronization, the proposed solutions apply to a wide variety ofimaging scenarios and situations.

In some example embodiments, in multi-imager environments such as amulti-image sensor device, cycling between illumination sources (forexample the near-field illumination source and the far-fieldillumination source) during symbol reading/decoding may introduce aflickering effect to an operator of the multi-image sensor device. Assuch, the illumination control framework may also include one or moreframeworks for flicker reduction. FIG. 13 illustrates an exampleworkflow of a general flicker reduction process 1300 executed by anexample multi-sensor imaging system, in accordance with at least oneexample embodiment of the present disclosure.

At 1302, the process 1300 includes operating a first illumination sourceassociated with a near field sensor, based on a first illumination pulsetrain. The first illumination source may be the near-field illuminationsource 106A discussed with reference to FIG. 2 . Accordingly, the firstsource illumination source may be operated in accordance with anear-field illumination pulse train such as the near-field illuminationpulse train 602 of FIG. 6 or the near-field illumination pulse train ofFIG. 11 . The first near-field illumination source may be configured toproduce pulsed illumination in the near-field of the imaging engine.Each individual pulse may be of a short duration such as 1.5 ms and maybe periodic or non-periodic with other illumination pulses of the pulsetrain.

At 1304, the process 1300 includes causing exposure of the near fieldsensor during a first exposure period. the start time period of thefirst exposure period may be substantially or fully aligned with a starttime period of an illumination period of the first illumination source.That is, the exposure of the near-field image sensor may commencesubstantially simultaneously with activation of the first illuminationsource as shown in the timing diagram 1100 of FIG. 11 . The exposure ofthe near-field image sensor may last for a period that ends beyond endof the illumination period of the first illumination source (i.e. beyondan activation period of the first illumination source).

At 1306, the process 1300 includes causing exposure of a far fieldsensor during a second exposure period, that does not overlap with anyillumination period of the first illumination source. For example, thefar-field image sensor of the imaging apparatus 200/imaging system 10may be exposed during a second exposure period. The start time periodand the end time period of the second exposure period of the far-fieldimage sensor may be scheduled in such a way that they do not overlapwith the illumination period of any illumination pulse of the near-fieldillumination pulse train. That is, the exposure of the far-field imagesensor may occur during a time period when the first illumination sourceis deactivated.

In this way, modifying the near-field illumination pulse train toaccommodate the far-field exposure period ensures that illuminationspill from far-field illumination does not occur into the exposure ofthe near-field image sensor and vice versa. Because the far-field imagesensor is exposed only during periods of deactivation of the near-fieldillumination source, there is no interference from the near-fieldillumination source in the exposure of the far-field image sensor. Also,such an arrangement ensures that the illuminations (near-fieldillumination and far-field illumination) are produced substantially insequence (i.e. no or very less time gap between the near-fieldillumination activation and far-field illumination activation forsuccessive pulses). Thus, an operator is not able to perceive anoticeable flicker caused by dimming and brightening of the illuminationsources.

In some example embodiments, the target to be captured may be at aconsiderable distance from the imaging engine. As such, capture of thetarget may be accomplished using the far-field image sensor. Further,such a scenario may amount to imaging from the farthest focal point(shortest focus) of the far-field image sensor which requires thelongest exposure of the far-field image sensor, for example when thefar-field image sensor includes a rolling shutter. In such scenarios,keeping the far-field illumination source activated for a long timeduration may introduce several issues with operation of the imagingengine such as excessive heat caused due to extended activation of thefar-field illumination source. Accordingly, for such scenarios aframework that reduces activation time of the far-field illuminationsource while ensuring that the far-field imaging is not compromised maybe desired. FIG. 14 illustrates an example workflow of a flickerreduction process 1400, specifically for extended far field exposures,executed by an example multi-sensor imaging system, in accordance withat least one example embodiment of the present disclosure.

Process 1400 includes at 1402, operating a first illumination sourceassociated with a near field sensor, based on a first illumination pulsetrain. Step 1402 may be executed in a manner similar to step 1302.

Process 1400 includes at 1402, causing exposure of the near field sensorduring a first exposure period, the start time period of the firstexposure period being aligned with a start time period of anillumination period of the first illumination source. Step 1402 may beexecuted in a manner similar to step 1304.

Process 1400 further includes at 1406, causing exposure of a far fieldsensor during a second exposure period, the second exposure periodoverlapping with at least one illumination period of the firstillumination source. For example, the far-field image sensor of theimaging apparatus 200/imaging system 10 may be exposed during a secondexposure period. In some example embodiments, the start time period orthe end time period of the second exposure period of the far-field imagesensor may be scheduled in such a way that the start time period or theend time period of the second exposure period of the far-field imagesensor is fully or substantially aligned with a start time period or endtime period of an illumination period of an illumination pulse pf thenear-field illumination pulse train. For example, as is shown in FIG. 6, the start time period of the far-field exposure pulse 614A is alignedwith the illumination pulse 602B of near-field illumination pulse train602.

In example contexts where the target to be captured falls in the centerregion of the field of view of the far-field image sensor, to extend theexposure time of the far-field image sensor the exposure can be modifiedso at most only a small number of the top and bottom rows of the rollingshutter based-far-field image sensor are exposed while the near-fieldillumination source is activated. This minimizes the reflections andlight leakage/illumination spill to the outer top and bottom areas ofthe far-field images ensuring that a minimum size region which in suchcontexts falls in the center region of the field of view of thefar-field sensor does not receive illumination from the near-fieldillumination source because it would interfere with automatic gaincontrol operations and general decoding. Thus, the resultant capturedimage is free from any adverse effect that might have been introduceddue to the illumination spill from the near-field illumination source.

It may be contemplated that within the scope of this disclosure, theminimum size region may be configurable by an operator/administrator ofthe imaging engine if the target to be captured falls in a region otherthan the center region of the field of view of the far-field imagesensor. That is, the minimum size region may be defined according toposition of the target to be captured in the field of view of thefar-field image sensor.

In this way, example embodiments of the flicker reduction process ofFIG. 14 provide efficient reduction in the perceivable flicker to anoperator by ensuring overlap between the exposure period of thefar-field image sensor and the illumination period of the near-fieldillumination source.

It will be understood that each block of the flowcharts and combinationof blocks in the flowcharts illustrated above in FIGS. 7, 8, 9, 10, 12A,12B, 12C, 13, and 14 may be implemented by various means, such ashardware, firmware, processor, circuitry, and/or other communicationdevices associated with execution of software including one or morecomputer program instructions. For example, one or more of theprocedures described above may be embodied by computer programinstructions. In this regard, the computer program instructions whichembody the procedures described above may be stored by a memory deviceof an apparatus employing an embodiment of the present invention andexecuted by a processor of the imaging apparatus/system. As will beappreciated, any such computer program instructions may be loaded onto acomputer or other programmable apparatus (for example, hardware) toproduce a machine, such that the resulting computer or otherprogrammable apparatus implements the functions specified in theflowchart blocks. These computer program instructions may also be storedin a computer-readable memory that may direct a computer or otherprogrammable apparatus to function in a particular manner, such that theinstructions stored in the computer-readable memory produce an articleof manufacture, the execution of which implements the function specifiedin the flowchart blocks. The computer program instructions may also beloaded onto a computer or other programmable apparatus to cause a seriesof operations to be performed on the computer or other programmableapparatus to produce a computer-implemented process such that theinstructions which execute on the computer or other programmableapparatus provide operations for implementing the functions specified inthe flowchart blocks.

Accordingly, blocks of the flowcharts support combinations of means forperforming the specified functions and combinations of operations forperforming the specified functions for performing the specifiedfunctions/operations. It will also be understood that one or more blocksof the flowcharts, and combinations of blocks in the flowcharts, can beimplemented by special purpose hardware-based computer systems whichperform the specified functions, or combinations of special purposehardware and computer instructions.

Although an example processing system has been described above,implementations of the subject matter and the functional operationsdescribed herein can be implemented in other types of digital electroniccircuitry, or in computer software, firmware, or hardware, including thestructures disclosed in this specification and their structuralequivalents, or in combinations of one or more of them.

Embodiments of the subject matter and the operations described hereincan be implemented in digital electronic circuitry, or in computersoftware, firmware, or hardware, including the structures disclosed inthis specification and their structural equivalents, or in combinationsof one or more of them. Embodiments of the subject matter describedherein can be implemented as one or more computer programs, i.e., one ormore modules of computer program instructions, encoded on computerstorage medium for execution by, or to control the operation of,information/data processing apparatus. Alternatively, or in addition,the program instructions can be encoded on an artificially generatedpropagated signal, e.g., a machine-generated electrical, optical, orelectromagnetic signal, which is generated to encode information/datafor transmission to suitable receiver apparatus for execution by aninformation/data processing apparatus. A computer storage medium can be,or be included in, a computer-readable storage device, acomputer-readable storage substrate, a random or serial access memoryarray or device, or a combination of one or more of them. Moreover,while a computer storage medium is not a propagated signal, a computerstorage medium can be a source or destination of computer programinstructions encoded in an artificially generated propagated signal. Thecomputer storage medium can also be, or be included in, one or moreseparate physical components or media (e.g., multiple CDs, disks, orother storage devices).

The operations described herein can be implemented as operationsperformed by an information/data processing apparatus oninformation/data stored on one or more computer-readable storage devicesor received from other sources.

The term “data processing apparatus” encompasses all kinds of apparatus,devices, and machines for processing data, including by way of example aprogrammable processor, a computer, a system on a chip, or multipleones, or combinations, of the foregoing. The apparatus can includespecial purpose logic circuitry, e.g., an FPGA (field programmable gatearray) or an ASIC (application-specific integrated circuit). Theapparatus can also include, in addition to hardware, code that createsan execution environment for the computer program in question, e.g.,code that constitutes processor firmware, a protocol stack, a repositorymanagement system, an operating system, a cross-platform runtimeenvironment, a virtual machine, or a combination of one or more of them.The apparatus and execution environment can realize various computingmodel infrastructures, such as web services, distributed computing andgrid computing infrastructures.

A computer program (also known as a program, software, softwareapplication, script, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, declarative orprocedural languages, and it can be deployed in any form, including as astand-alone program or as a module, component, subroutine, object, orother unit suitable for use in a computing environment. A computerprogram may, but need not, correspond to a file in a file system. Aprogram can be stored in a portion of a file that holds other programsor information/data (e.g., one or more scripts stored in a markuplanguage document), in a single file dedicated to the program inquestion, or in multiple coordinated files (e.g., files that store oneor more modules, sub-programs, or portions of code).

The processes and logic flows described herein can be performed by oneor more programmable processors executing one or more computer programsto perform actions by operating on input information/data and generatingoutput. Processors suitable for the execution of a computer programinclude, by way of example, both general and special purposemicroprocessors, and any one or more processors of any kind of digitalcomputer. Generally, a processor will receive instructions andinformation/data from a read-only memory or a random-access memory orboth. The essential elements of a computer are a processor forperforming actions in accordance with instructions and one or morememory devices for storing instructions and data. Generally, a computerwill also include, or be operatively coupled to receive information/datafrom or transfer information/data to, or both, one or more mass storagedevices for storing data, e.g., magnetic, magneto-optical disks, oroptical disks. However, a computer need not have such devices. Devicessuitable for storing computer program instructions and information/datainclude all forms of non-volatile memory, media and memory devices,including by way of example semiconductor memory devices, e.g., EPROM,EEPROM, and flash memory devices; magnetic disks, e.g., internal harddisks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROMdisks. The processor and the memory can be supplemented by, orincorporated in, special purpose logic circuitry.

To provide for interaction with a user, embodiments of the subjectmatter described herein can be implemented on a computer having adisplay device, e.g., a CRT (cathode ray tube) or LCD (liquid crystaldisplay) monitor, for displaying information/data to the user and akeyboard and a pointing device, e.g., a mouse or a trackball, by whichthe user can provide input to the computer. Other kinds of devices canbe used to provide for interaction with a user as well; for example,feedback provided to the user can be any form of sensory feedback, e.g.,visual feedback, auditory feedback, or tactile feedback; and input fromthe user can be received in any form, including acoustic, speech, ortactile input. In addition, a computer can interact with a user bysending documents to and receiving documents from a device that is usedby the user; for example, by sending web pages to a web browser on auser's client device in response to requests received from the webbrowser.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anydisclosures or of what may be claimed, but rather as descriptions offeatures specific to particular embodiments of particular disclosures.Certain features that are described herein in the context of separateembodiments can also be implemented in combination in a singleembodiment. Conversely, various features that are described in thecontext of a single embodiment can also be implemented in multipleembodiments separately or in any suitable sub-combination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asub-combination or variation of a sub-combination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the embodiments described above should not be understoodas requiring such separation in all embodiments, and it should beunderstood that the described program components and systems cangenerally be integrated together in a single software product orpackaged into multiple software products.

Thus, particular embodiments of the subject matter have been described.Other embodiments are within the scope of the following claims. In somecases, the actions recited in the claims can be performed in a differentorder and still achieve desirable results. In addition, the processesdepicted in the accompanying figures do not necessarily require theparticular order shown, or sequential order, to achieve desirableresults. In certain implementations, multitasking and parallelprocessing may be advantageous.

1-20. (canceled)
 21. An imaging system, comprising: a first image sensorassociated with a first illumination source, wherein the first imagesensor is configured to capture a first image of a target symbol; asecond image sensor; and a controller comprising processing circuitry,the controller communicatively coupled to the first illumination source,the first image sensor, and the second image sensor, wherein thecontroller is configured to: process the first image to estimatedistance between the first image sensor and the target symbol; determinea first exposure period of the second image sensor based on the distanceestimation; and modify one or more characteristics of the first exposureperiod of the second image sensor based on at least one illuminationpulse of the first illumination source.
 22. The imaging system of claim21, wherein the one or more characteristics of the first exposure periodof the second image sensor comprise a minimum size region defined basedon a position of the target symbol to be captured in a field of view ofthe second image sensor.
 23. The imaging system of claim 21, wherein thecontroller is further configured to: determine whether decoding of thetarget symbol is successful based on the image processing of the firstimage; and change a focus position of the second image sensor when thedecoding is unsuccessful.
 24. The imaging system of claim 23, whereinthe controller is further configured to change the focus position basedon the distance estimation.
 25. The imaging system of claim 21, whereinto modify the one or more characteristics of the first exposure periodof the second image sensor, the controller is further configured tofully or substantially align a start time period or an end time periodof the first exposure period of the second image sensor with a starttime period or an end time period of an illumination period of the atleast one illumination pulse of the first illumination source.
 26. Theimaging system of claim 21, wherein to modify the one or morecharacteristics of the first exposure period of the second image sensor,the controller is further configured to avoid overlapping of the firstexposure period of the second image sensor with the at least oneillumination pulse of the first illumination source.
 27. The imagingsystem of claim 26, wherein to avoid overlapping of the first exposureperiod of the second image sensor with the at least one illuminationpulse of the first illumination source, the controller is furtherconfigured to deactivate the first illumination source during the firstexposure period of the second image sensor.
 28. The imaging system ofclaim 26, wherein to avoid overlapping of the first exposure period ofthe second image sensor with the at least one illumination pulse of thefirst illumination source, the controller is further configured toschedule a start time period and an end time period of the firstexposure period of the second image sensor to not overlap with the atleast one illumination pulse of the first illumination source.
 29. Theimaging system of claim 21, wherein the controller is further configuredto: obtain an image frame captured by exposure of the second imagesensor during the first exposure period; determine brightness of theimage frame; and activate a second illumination source associated withthe second image sensor, based on the determined brightness of the imageframe.
 30. The imaging system of claim 21, wherein exposure of the firstimage sensor begins simultaneously with activation of the firstillumination source.
 31. An imaging method, comprising: operating afirst image sensor associated with a first illumination source, whereinthe first image sensor is configured to capture a first image of atarget symbol; processing the first image to estimate distance betweenthe first image sensor and the target symbol; determining a firstexposure period of a second image sensor based on the distanceestimation; and modifying one or more characteristics of the firstexposure period of the second image sensor based on at least oneillumination pulse of the first illumination source.
 32. The imagingmethod of claim 31, wherein the one or more characteristics of the firstexposure period of the second image sensor comprises a minimum sizeregion defined based on a position of the target symbol to be capturedin a field of view of the second image sensor.
 33. The imaging method ofclaim 31, further comprising: determining whether decoding of the targetsymbol is successful based on the image processing of the first image;and changing a focus position of the second image sensor when thedecoding is unsuccessful.
 34. The imaging method of claim 33, whereinthe focus position is changed based on the distance estimation.
 35. Theimaging method of claim 31, wherein modifying the one or morecharacteristics of the first exposure period of the second image sensorcomprises fully or substantially aligning a start time period or an endtime period of the first exposure period of the second image sensor witha start time period or an end time period of an illumination period ofthe at least one illumination pulse of the first illumination source.36. The imaging method of claim 31, wherein modifying the one or morecharacteristics of the first exposure period of the second image sensorcomprises avoiding overlapping of the first exposure period of thesecond image sensor with the at least one illumination pulse of thefirst illumination source.
 37. The imaging method of claim 36, whereinavoiding overlapping of the first exposure period of the second imagesensor with the at least one illumination pulse of the firstillumination source comprises deactivating the first illumination sourceduring the first exposure period of the second image sensor.
 38. Theimaging method of claim 36, wherein avoiding overlapping of the firstexposure period of the second image sensor with the at least oneillumination pulse of the first illumination source comprises schedulinga start time period and an end time period of the first exposure periodof the second image sensor to not overlap with the at least oneillumination pulse of the first illumination source.
 39. The imagingmethod of claim 31, further comprising: obtaining an image framecaptured by exposure of the second image sensor during the firstexposure period; determining brightness of the image frame; andactivating a second illumination source associated with the second imagesensor, based on the determined brightness of the image frame.
 40. Theimaging method of claim 31, wherein exposure of the first image sensorbegins simultaneously with activation of the first illumination source.